In large sections of the United States and other parts of the world the land is uniquely suitable for the growth of alfalfa as a stock feed. Irrigation projects have increased the amount of land available for the cultivation of alfalfa and, as a result, there is a continuing demand for alfalfa seed. Since alfalfa is an annual and must be reseeded each year for continuing production, a problem in the expansion of alfalfa production has been a lack of sufficiently large supplies of seed. Under current technology, production of alfalfa seed has been somewhat of a gamble for the farmer since, along with problems of water, soil, weather and insects that harass all farming endeavors, there is the additional problem that alfalfa is not wind pollinated as are many other crops. Attempts have been made to pollinate alfalfa by mechanical devices such as dragging chains across the fields. These approaches have not achieved any appreciable commercial success.
Search for a means of pollination of alfalfa has thus turned largely to the different species of bees. In the states of California and Utah, for instance, some success has been obtained by the use of honey bees for pollination in the production of alfalfa seed but this approach has been generally accepted. In several of the western United States the akali bee (Nomia melanderi), a native species which nests in soil that is firm and moist and relatively free of vegetation, is also used for pollination. Although the alkali bee has not been domesticated, by encouraging propagation, the yield of alfalfa seed can be significantly increased. Reliance must be had on nature, to a large degree, for supply and upkeep of the quantity of bees needed for pollination.
A second bee species, the leafcutter bee (Megachile rotundata), is assuming ever greater importance for pollination of alfalfa crops in the western United States and Canada. This species, originally a native of middle eastern Europe, will nest in holes left by boring insects, typically in rotting wood. It will, however, readily accept artificial nests and is quite gregarious, several bees nesting close together, thus widespread domestication has occurred.
Several types of nests for leafcutter bees have been developed, perhaps the simplest being a wooden block with approximately 3/16th inch diameter holes drilled into its face to provide nesting holes. The blocks are placed in shelters on the edges of the alfalfa fields during the nesting season. While the raw-material of the nesting block is relatively inexpensive, the labor involved in drilling large numbers of holes and the practice of discarding the block at the end of one season due to the difficulty in cleaning renders them relatively unsatisfactory for most growers. Another very inexpensive form of leafcutter bee nest may be made simply by using a box of drinking straws of the appropriate length, open at one end exposing the interiors of the straws. Although the straws are inexpensive and may be conveniently disposed of at the end of the season, eliminating cleaning problems, the high vulnerability to parasites, to the sacrifice of the bee larvae, presents a serious problem.
With the increase in leafcutter bee populations there has been a corresponding increase in the numbers and effects of parasites. In excess of thirty parasites and other natural enemies have been identified, the most common and destructive parasite being a wasp (Monodontomerus obscurus). This wasp lays eggs in the nests which hatch into larvae that devour the bee larvae. Among the other enemies of the leafcutter bee are so called "nest destroyers" which are stored-products pests which simply destroy bee larvae in the process of feeding through the nest materials. The most common of these are the carpet beetle (Trogoderma glabrum), the red flower beetle (Tribolium castaneum), the checkered flower beetle (Trichodes ornatus) and the dried-fruit moth (Vitula edmandsae serratilineela). The presence of these pests and their larvae requires thorough cleaning and sterilization of the bees' nests at the end of each season to control their spread and to maintain bee population. These conditions have led to the need for the development of new forms of nesting structures which are more nearly parasite proof and/or cleanable and reusable. The economics of maintaining large numbers of nests has also become a prime factor in the alfalfa seed growing industry.
The first type of truly reusable and cleanable nest or hive developed comprised a plurality of wooden boards having parallel grooves on both faces. The boards are stacked and held in a frame with the aligned grooves in the mating faces forming nesting holes. At the end of each season the grooved boards are removed from the frames and cleaned and sterilized. Certain problems arise with the use of wooden boards, however, due to the porous nature of the material and the difficulty in obtaining thorough cleaning. In recent years use of wooden boards has given way to more expensive polystyrene boards in attempts to solve the cleaning problems. In any case the advent of the grooved board nest has made it possible to remove the larvae before they are mature and place them in incubators. By use of optimum temperature incubators the time required for maturity of the bees is lessened and a greater ultimate number of bees may be produced from a given number of starting bees. Additionally, the complete domestication and control of the life cycle of the leafcutter bee allows greater control of parasitic insects and other natural enemies such as birds, rodents and the like. The major problem remained, however, in devising inexpensive and efficient means for removing bee larvae from the nests without injuring the larvae or damaging the nests.
Originally the bee larvae had to be scraped from the individual grooves in the boards by hand using a knife or other instrument which was a time consuming and expensive task. Early efforts to mechanize the cleaning process involved such apparatus as devices for holding the boards and moving them past fixed wooden teeth arranged to scrape and clean the grooves. More recently mechanical devices have been designed for the purpose of separating the grooved boards, scraping the larvae from the grooves and collecting and separating the larvae from nest debris. One such known device is disclosed in the Theodore C. Barber, U.S. Pat. No. 3,965,509.
An improved spirally wound type of nest has come into existence in the past few years which offers many advantages over prior devices in terms of economy, ease of handling and improved protection against parasites. Originally the nest or hive consisted essentially of an approximately 4 inch wide spirally wound strip of corrugated paper of the type used in cardboard box making. The flutes of the corrugated strip, when wound on itself in spiral fashion, provide a multitude of nesting holes for the leafcutter bees. Although the first such nests were made of paper and were discarded at the end of each season, improvements have led to the use of ABS plastic or other polymeric material for the corrugated strip and a separator strip is now wound with the corrugated strip to separate the layers of corrugations. The preferred material for the separator strip is a flexible foam material which prevents migration of parasites between the layers of the corrugated strip. The walls of the corrugated strip act to prevent such parasites from boring between the walls of the larvae cells. To process the bee larvae, the spiral nest must be unwound, the larvae extracted from the flutes on both sides of the corrugated strip, both strips cleaned and subsequently rewound for reuse. This process, of course, has given rise to the need for an apparatus and method hitherto unknown in the art for carrying out these steps. The present invention provides a novel apparatus and method for accomplishing these steps in a highly efficient and economical manner.